I really loved the previous DOW games so I was really looking forward to this but was left feeling a little deflated by it. Firstly they have put the Dark Eldar in which is probably the least popular army in 40k. The hell with the 'plot' they should have put Tyranids in instead. As for the plot, some of the voice acting is laughable, especially the Imperial Gaurd's level where there are long pauses between dialogue and the characters are poorly scripted. You have to watch it to see how bad that scene is between the Commissar and the General.
My biggest problem though is that there isn't really any change from DC. the aerial units are a cheap add on that offer no real update to this francise. There are a few strange annoyances like when you conquer a territory anything you built is gone if it comes under attack which makes defending a tedious chore.
Also the single player gets really monotinous as there are 39 territories to conquer which involve the same routine every time. Attck area, build base/army, destroy enemy base, move to new area and repeat. With 9 armies in the game it is a little too big and I got seriously bored after trying the single player during the 3rd army. I haven't even bothered with the other 6 cos they are exactly the same as in DC.
I'm not saying it's a bad game, far from it. I really like the Sisters of Battle. It's just that this is just DC with 2 new armies 'tacked' on and that's it. It has a very rushed feel to it. Also the load times are horrendous and I have had issues with my copy crashing and losing the saved data, which was a bugger playing as Tau as I was on the very last level and have to start all over again.
If you haven't bought any of the Dawn of War games yet I can only really recommend getting the 1st 3 (Dawn if War, Winter Assault & Dark Crusade), get the anthology edition as it's cheapest option to get all 3 in 1. Everything in this game is exactly the same as in DC so a bit much to ask to fork out the money on buying.
I am eagerly awaiting Dawn of War 2, I just hope to god that they put some effort into it unlike Soul Storm.